arrify 
Convert a value to an array
Install
$ npm install --save arrify
Usage
const arrify = require('arrify');
arrify('unicorn');
//=> ['unicorn']
arrify(['unicorn']);
//=> ['unicorn']
arrify(null);
//=> []
arrify(undefined);
//=> []
Supplying null or undefined results in an empty array.
License
MIT © Sindre Sorhus